Pen



FIG. 1 is a perspective view of a pen showing my new design;

FIG. 2 is an elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a perspective partly exploded view thereof with the pen point retracted; and

FIG. 6 is a perspective partly exploded view thereof with the pen point extended. 

The ornamental design for a pen, as shown and described. 